O caquizeiro (Diospyros kaki L.) é uma planta caducifólia pertencente à família Ebenaceae, tendo como centro de origem a região central da China. Entre os estados brasileiros, São Paulo é o que apresenta maior produção de caquis com 49.727 t. A cercosporiose (Pseudocercospora kaki), também conhecida como mancha angular, é a principal doença foliar da cultura. Alguns autores atribuem à cercosporiose a queda precoce de folhas, maturação antecipada dos frutos e a redução da produção na safra seguinte. Entretanto, não existem trabalhos com o patossistema P. kaki - D. kaki que deem suporte a essas pressuposições. Diante disso, os objetivos desse trabalho foram comparar a susceptibilidade de quatro cultivares de caquizeiro e avaliar o efeito da cercosporiose na fisiologia da planta. Os experimentos foram conduzidos em condições naturais de campo, com as cultivares Fuyu, Rama Forte, Taubaté e Giombo, por serem as mais cultivadas no estado de São Paulo. Nos experimentos desenvolvidos buscou-se conhecer o grau de resistência das quatro cultivares à cercosporiose, avaliando a incidência, severidade e queda de folhas ao longo de dois ciclos de cultivo, assim como avaliar o controle químico na redução da doença em cvs. Taubaté e Rama Forte e, consequentemente, no acúmulo de reservas na raiz e na qualidade dos frutos colhidos. Foram avaliadas também os danos na fotossíntese em folhas das quatro cultivares com diferentes intensidades de cercosporiose. Como resultados pode-se constatar, que a cv. Fuyu é a mais susceptível à cercosporiose, seguida com resistência média \'Giombo\' e \'Rama Forte\' e com maior resistência a cv. Taubaté. A intensidade da cercosporiose, para severidades da doença de até 7% não influencia na queda de folhas. O controle químico reduziu a intensidade de doença nas cvs. Taubaté e Rama Forte, entretanto, entre as intensidades de cercosporiose avaliadas em plantas tratadas e não tratadas, não há redução no acúmulo de reservas no sistema radicular, assim como na qualidade físico-química dos frutos colhidos. Mesmo a cercosporiose afetando a fotossíntese, no processo fotoquímico, tanto na área lesionada como na área adjacente à lesão, a intensidade da doença observada no campo não foi suficiente para causar redução da produção à cultura. / The persimmon (Diospyros kaki L.) is a deciduous plant of the botanical family Ebenaceae, native to central China. Among the Brazilian states, São Paulo has the highest production of persimmon with 49,727 ton/year. The angular leaf spot of persimmon (Pseudocercospora kaki), also known as cercosporiosis, is the main leaf disease of the crop. Some authors attribute to the cercosporiosis the premature defoliation, early maturation of the fruits and the reduction of the yield in the next crop cycle. However, there are no previous studies with the Pseudocercospora kaki pathosystem that support these hypotheses. Therefore, the objectives of this study were to compare the susceptibility of four persimmon cultivars and evaluate the effect of angular leaf spot on plant physiology. A field experiment was conducted with Fuyu, Rama Forte, Taubaté and Giombo cultivars, the four most cultivated in the state of São Paulo. The degree of resistance to cercosporiosis was determined by the incidence and severity of the disease and by defoliation of the plants in two crop cycles. Chemical spraying for the disease reduction was also evaluated in cvs. Taubaté and Rama Forte. The reduction of the carbohydrate reserve accumulation in the roots and the quality of the fruits harvested were tested. The photosynthesis reduction was also evaluated in leaves of the four cultivars with different intensities of cercosporiosis. The Fuyu cultivar was the most susceptible to cercosporiosis, followed by moderate resistance of \'Giombo\' and \'Rama Forte\' and high resistance of cv. Taubaté. The intensity of cercosporiosis, for disease severity up to 7% does not influence leaf drop. Though the chemical control reduced the disease intensity in cvs. Taubaté and Rama Forte, treated and untreated plants showed no differences in the reserves accumulation in the roots, as well as in the physicochemical quality of the harvested fruits. Even though cercosporiosis affects photosynthesis in the photochemical process on both the necrotic and remaining green leaf area, the intensity of the disease observed in the field was not enough to cause yield reduction to the culture.

Thesis advisor: Fabio Ghironi / Thesis advisor: Christopher Baum / My dissertation focuses on the macroeconomics of emerging and developing nations. This group of economies is characterized by significant differences in terms of institutional quality, financial development, as well as other cultural, social, political parameters. In turn, these structural heterogeneities exert considerable influence on their domestic economic environment, specifically impacting key macroeconomic indicators such as output, investment, consumption, foreign capital flows, exchange rates etc. Understanding these nuanced relationships and analyzing them from various dimensions has served as the motivation and the foundation of my doctoral research. The first essay is an empirical and theoretical investigation of Business Cycles and Macroeconomic Dynamics in post-independence India. India's growth performance was touted as ordinary relative to the rest of the world during the first three decades after it gained independence in 1947. However, path-breaking deregulation and liberalization reforms in the 80s and 90s led to substantial growth acceleration and India's metamorphosis into a market-based economic system with strong international ties. This makes the Indian case study really unique and fascinating. Using annual time series data, we document key business cycle properties of the Indian economy. Output, consumption and investment are more volatile in India compared to its developed country counterparts. As in developed countries, consumption is less volatile and investment is more volatile than output in the Indian data. In contrast, investment is not highly correlated with output in India. Moreover, India's economic landscape has undergone significant changes, both in terms of the absolute level and cyclical fluctuations, across the planning horizon. The presence of structural break is reported for major macroeconomic variables when we decompose the data into pre- and post-reform categories. We also test whether a standard real business cycle (closed economy) model with India-specific parameters can replicate the stylized features of the business cycle. The model includes a tax on capital income which acts as a disincentive for future investment, and the results indicate that a high volatility of the tax shock is required to produce the low investment output correlation. The model performs reasonably well in matching the correlation dynamics observed in the data. In the second essay, I examine Foreign Reserve accumulation in Developing Countries through the lens of Institutional Quality and Financial Development. In recent times, several emerging markets have been providing the rest of the world, and especially the United States, with net resources in the form of current account surpluses. The most noteworthy aspect of the surge in upstream foreign capital flows has been the enormous increase in international reserves held by several emerging economies. Whereas private capital flows are broadly in sync with the standard neoclassical model, capital outflows from relatively high-productivity emerging markets can be explained by the accumulation of official reserve assets. I investigate the foreign reserve dynamics in developing countries; from both an empirical and theoretical dimension. Using a novel panel dataset combining aspects of openness, institutional quality, and financial development and an innovative clustering method; I present a new approach to identify cross-national structural heterogeneity and assess its relationship with foreign reserves. I use partition-based cluster analysis to document underlying reserve dynamics and identify systematic variation across and between different country groups. The resulting cluster outputs reflect the presence of cross-national variations in reserve accumulation. Moreover, a series of the scatter plots encapsulating various dimensions of institutional quality and financial development points towards the resounding presence of structural heterogeneity in foreign reserve dynamics in our developing country sample. Cross section and panel data regressions reinforce the initial hypotheses concerning the role of institutional and financial development in international reserve dynamics of the developing world. I also build a theoretical model embedding the key insights from the empirical analyses in order to propose a coherent framework for explaining the link between institutions, financial development reserve accumulation. The model underscores the importance of financial market efficiency and the institutional environment in explaining reserve dynamics of major developing countries. A series of comparative static exercises shed light on the impact of heterogeneity in institutional parameters and foreign reserve policy on select macroeconomic variables. In a nutshell, by going beyond the regional differences, we provide a unique vantage point to understand how disparities in institutional and financial conditions influence reserve dynamics in different country clusters. Our results indicate that income, openness, institutional quality and financial development play an instrumental role in explaining the underlying patterns of reserves accumulation in the developing world. However, the effects of these structural indicators are markedly different across clusters of relatively similar countries in terms of their magnitude as well as direction. / Thesis (PhD) — Boston College, 2014. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Economics.